1) Field
Embodiments of the present invention pertain to the field of semiconductor processing equipment and, in particular, to electrostatic chucks with variable pixelated magnetic field.
2) Description of Related Art
In a plasma processing chamber, such as a plasma etch or plasma deposition chamber, the plasma density is often an important parameter to control during a process since it can correspond to the amount of ionization available at a location within the plasma.
Often, plasma density is manipulated by thermal means, where a change in the temperature of the plasma can lead to a change in plasma density. For example, a temperature of a substrate holder, commonly called a chuck or pedestal, may be controlled to heat/cool a workpiece to various controlled temperatures during the process recipe (e.g., to control an etch rate). Similarly, a temperature of a showerhead/upper electrode, chamber liner, baffle, process kit, or other component may also be controlled during the process recipe to influence the processing. Conventionally, a heat sink and/or heat source is coupled to the processing chamber to maintain the temperature of a chamber component at a desired temperature. Often, at least one heat transfer fluid loop thermally coupled to the chamber component is utilized to provide heating and/or cooling power. Long line lengths in a heat transfer fluid loop, and the large heat transfer fluid volumes associated with such long line lengths are detrimental to temperature control response times. Point-of-use systems are one means to reduce fluid loop lengths/volumes. However, physical space constraints disadvantageously limit the power loads of such point-of-use systems.
With plasma processing trends continuing to increase RF power levels and also increase workpiece diameters (with 300 mm now typical and 450 mm systems now under development), temperature and/or RF control and distribution addressing both a fast response time and high power loads is advantageous in the plasma processing field. Temperature-based or temperature-only solutions may not achieve the optimal tunability of plasma density. As such, advances are still needed toward plasma density tunability.